Lifelong Giants fan here, so I'll give my perspective. I'd like to keep Bumgarner and maybe ship off a reliever (Watson) to address something like infield help.
The thing about the Giants is that the WS teams never looked good on paper. That's why it's no surprise Derka says they wouldn't compete against the Yankees, Astros, etc. that are far more talented. But guys like Aubrey Huff, Cody Ross, Travis Ishikawa and Marco Scutaro were the reasons the team hung 3 banners in 5 years. Not exactly household or marquee names.
Giants teams have always relied on solid rotation, good bullpen and timely hitting from guys that rise up at the right moments. Zaidi seems to have found one of those Huff, Ross, Scutaro types in Alex Dickerson. He's not exactly a journeyman, but he was written off by the Padres and has found new life with the Giants. The other core guys from past WS teams that have either battled injuries or slumps are all showing glimpses of returning to their former selves albeit older. Posey, Belt, Crawford and Panik are seasoned guys when it comes to October baseball, so it would be interesting to see how they step up if given a chance in the playoffs.
The other thing no one has talked about is the return of Cueto. He's facing live batters now and is on track to return in September. Bum - Cueto as a 1-2 could make things interesting from a top of the rotation perspective especially combined with the Giants' deep, quality relief staff. A lot of the elements that were there in '10, '12, '14 and even '16 (eliminated by the eventual WS Champion Cubs) are there again with this '19 team.
Of course, they can't keep winning at this pace (17-3 in last 20 games). They can only hope this type of baseball and mentality will continue, and maybe it will be enough to earn them a WC berth.